Unfortunately you will be unable to remove signatures from the message body directly with Mail Disclaimers, however we recommend removing existing Outlook signatures using a Group Policy. You will have to remove mobile device signatures manually.

I'm not using exclaimer, but what I have on one of our clients is in the MailFlow Disclaimer rule I have set it so that it always add the signature unless it detects the text we have in the disclaimer so then it does not add it again - being what disclaimers are this saves a lot of space and "read time" as you don't have to skip past multiple disclaimers to get to the part of the eMail you want..